Supervisory system for detecting suspended matter in fluids



Oct. 27, 1931. FREYGANG 1,828,894

SUPERVISORY SYSTEM FOR DETECTING SUSPENDED MATTER IN FLUIDS Filed 0g. 50, 1928 11V VE N TOR the detecting apparatus become inoperative,

Patented Oct. 27, 1931 UNITED STATES PATENT OFFICE ousTAv GEORGE FBEYGANG, or wmmAwxnn, NEW mnszr, ASSIGNOB To WALTER mm: & comrAmr, nm, or new max, 1:. Y., A coaroaATron or new YORK surnnvrsomr mm non DETECTING svsrnmmn MATTER 1n rrurns Application filed October 80, 1928. Serial No. 818,085.

the system which would cause itto fail to operate.

In the copending application of Walter H. Freygang,. Serial N 0. 116,522 filed June 17, 1926, there is disclosed a device for detecting the presence of suspended matter in fluids by means of the reflection of light from such suspended matter upon a light-sensitive or photo-electric cell. The cell is normally unilluminated and a beam of light from a pilot lamp passes through a detecting chamber in sue manner that its rays do not fall upon the lightsensitive cell.. If the fluid in the detecting chamber contains suspended matter, the beam of light strikes such matter and the light rays reflected therefrom fall upon the light-sensitive cell to indicate such condition. The present invention embodies the fundamental principles of the system disclosed in the foregoing application, and additionally provides a means for maintaining a supervisory current in the main alarm circuit by means of a supervisory light which is caused to fall upon the light-sensitive cell. The supervisory current is of insufiicient magnitude to operate the main alarm signal, and hence the main alarm circuit is in a nonsignaling condition. Should or some reason exist for causing it to fail to operate, as by a wire break, the failure of any of the essential parts of the apparatus or the failure of the supervisory light itself, the su pervisory current will be interrupted. The interruption of the supervisory current can be utilized for indicating the existence of such inoperative condition in order that it may be overcome.

Further .features of the invention will appear as it is described more fully in connection with the accompanying drawings, wherein: K

Figure 1 is a view in section through a proposed form of detecting chamber showing the detecting apparatus mounted to indicate the desired conditions.

Figure 2 is a view similar to Figure 1, showing a slightly modified construction.

Figure 3 is a diagrammatic representation of a suitable arrangement of photo-electric cell, amplifier, alarms and relays.

Referring to the drawings, a designates a detecting chamber into which a fluid stream may be introduced at a. This fluid stream may constituteair from a compartment which is to be protected against fire, and the stream, upon the existence of fire within the area to be protected, will be laden with smoke particles which will be introduced into the detecting chamber a. The stream flows out of the detecting chamber at (1 thus completing the circuit through such chamber.

A com artment b is formed in the detecting cham er by means of a partition 12 within which is mounted a lens 6 A slight source 0 is mounted within the compartment 6, preferably at the focal point of lens 6 in order that parallel rays may be directed through the detecting chamber a. A portion of these rays constituting a suitable beam of light 1s indicated at o and a screen 0 provided with an aperture 0 is mounted in the detecting chamber to prevent the existence of diverging rays in the beam of light a.

A second compartment (1 is formed in or communicates with the detecting chamber and provided with a photo-electric cell 6 connected in a suitable circuit, the wires of which are indicated at e. An aperture (1 is formed in the compartment d though which light rays reflected from smoke particles or other suspended matter ass. The screen 0 is provi ed with an additional aperture 0 through which a beam of light 0' from the light source 0 may pass. This beam of light falls upon a mirror 9 and is reflected through the aperture d, thus falling upon the photo-electric cell e. In this construction, the supervisory light is the main light source a, and the system is of such character that an fault will be detected, whether in the lig t source or in the alarm c1rcu1t.

In the modified form shown in Figure 2,

a supervisory light source f, comprising an auxiliary lamp, is mounted. in the detectin chamber immediately below the aperture in order that rays of light therefrom may I pass through such aperture and fall upon the photo-electric cell e. The lamp constituting this superviso light source may be connected in a suitab e circuit, the wires of'which are indicated at f.

Figure 3 indicates, diagrammatically, a suitable electric alarm circuit. The photoelectric cell e is connected through wires e with a resistance It and battery i. Switch i permits the system to be rendered opera- 15 tive or inoperative at will. A thermionic tube 7' receives its input current through wires j which are mounted across the resistance 72..

The plate circuit of the thermionic tube includes a variable resistance 70, battery 2', noload relay Z and overload relay Z. Wire 7" connects these elements in operative relation with the thermionic tube. Suitable alarms m and m are operated by the respective relays Z and Z to indicate the existence of a 2i faulty condition, or the presence of smoke,

respectively.

In the construction shown in Figure 1, the li ht from the mirror 9 is continually directof upon the photo-electric cell to reduce the resistance thereof sufliciently to cause a predetermined current flow through the circuit formed by the wire 7'. This current flow is insuflicient to cause overload relay Z to function and suflicient to hold no-load relay Z from operating. Should the apparatus become inoperative, the flow of the supervisory current will cease and no-load relay I will function. Should the fluid stream be laden with smoke particles, the resistance of the photo-electric cell will be further decreased by reason of the added light intensity falling thereon from the reflection and refraction of light by the smoke particles. This causes an increase of current in the circuit formed by the wire 1' to cause the overload relay Z to function, thus sounding the appropriate alarm.

In the form shown in Figure 2, the operation described above takes place, the only difference being that the supervisory light source is an auxiliary lamp.

It will be seen that the system described above operates upon the principle of fluctuating currents, the polarities or relative directions of flow of several currents having no 'vital eflect upon the system. The device is highly efl'ective in operation, not only detecting the minutest presence of smoke, but also instantaneously indicating the existence of trouble in the apparatus itself in order that it may be repaired in good season.

I claim as my invention 1. The method of detecting suspended matter in fluids which consists in causing light rays to fall upon a photo-electric element condition, providing a beam of light, directing the fluid stream to cause light from the beam to be reflected and refracted upon the element to cause an abnormal and changed condition, and causing a changed condition to produce an alarm signal.

3. The method of detecting suspended matter in fluids which consists in causing light rays to fall directly upon a ph0t0-electric element to produce a normal current flow, causing the normal current flow to energize an alarm circuit, causing additional light rays I to fall upon a photo-electric element by reflection and refraction to cause an abnormal current flow and causing the abnormal current to energize the alarm circuit to produce an alarm signal due to the additional light 1'8. S-

1. Means for detecting the presence of suspended matter in fluids com rising a photoelectric element, means to irect light rays upon the element, a light source, means to direct the fluid stream in the path of light from the li ht source to cause light to be reflected an refracted upon the photo-electric element, an alarm control circuit, alarm operating'means in the circuit responsive to increases and decreases of current therein whereby the variations of light from the source and directing means produce fluctuations in the current in the alarm control circuit.

5. Means for detecting the presence of suspended matter in fluids comprising a photoelectric element, a circuit including the photo-electric element, a primary source of light, means to cause light from said primary source to fall upon the photo-electric element and thereby produce a normal current flow in said circuit, a second source of light, means to direct the fluid stream in the path of light from the last named source and thereby to cause light to be reflected and refracted upon the photo-electric element, means responsive to an increase of current in said circuit, and means in said circuit responsive to a decrease in the current therein.

6. Means for detecting the presence of suspended matter in fluids comprising a photoelectric element, means to direct light rays normally upon the element to maintain a normal resistance value thereof, an alarm control circuit connected to the element through which a supervisory current normal:

ly flows due to the resistance of the element,

' Octobe 10 a light source, means to conduct the fluid in a path to cause the suspended matter carried therebi to reflect and refract light upon the photo-e ectric element to increase the current in the circuit, and an alarm operating means in the alarm control circuit responsive to increases and decreases of current therein. This sgecification signed this 11th day of GUSTAV G. FREYGANG. 

